Frank, 71, is the ranking member on the Financial Services Committee, and the financial reform measure passed last year bears his name.

State leaders lauded Frank's years of service, with Massachusetts Democratic Party Chairman John Walsh saying in a statement that Frank "will take his place in history as a shining son of Massachusetts."

The news comes about a month after Rep. John Olver (D-Mass.) announced his retirement and just after Gov. Deval Patrick signed the new Congressional map. The new lines significantly shifted Frank's 4th district.

The newly drawn 4th meanders from his longtime base of support in liberal Newton and Brookline down to a portion of Fall River. It will remain a Safe Democratic seat.

Some possible Democratic candidates include City Year co-founder Alan Khazei, who recently dropped his Senate primary bid, former Brookline Board of Selectman Chairwoman Deborah Goldberg, Brookline Selectwoman Jesse Mermell, state Sen. Cynthia Creem and Bristol County District Attorney Samuel Sutter.

A Massachusetts Democratic official told Roll Call that Newton Mayor Setti Warren, who dropped out of the race for Senate, was unlikely to make a bid for Congress and instead will focus on running his city.

Walsh struck a political tone when honoring Frank.

"In 2010, Republicans made an all-out push to stem the tide of Democratic progress in Massachusetts and thanks to our better ideas, better candidates and a massive grassroots campaign that stretched from one corner of the Commonwealth to the other, that push fell short," Walsh said in the statement. "Next year, we will mount an even bigger grassroots effort to build on the gains we made in 2010 and continue to move Massachusetts forward."

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March 13, 2015

Tom Williams/CQ Roll Call

Rep. Elijah Cummings, D-Md., right, hugs Harold Schaitberger, General President of the International Association of Fire Fighters, after the Congressman spoke at the IAFF's Legislative Conference General Session at the Hyatt Regency on Capitol Hill, March 9, 2015. The day featured addresses by members of Congress and Vice President Joe Biden.